Practice ammunition rounds



March1 1,1958 R. N. SANDBERG ETAL 2,826,145

' PRACTICE MMIIUNITIONROUNDS I Filed NOV. 26, 1954 5 Sheets-Sheet- 1 A I 20 L 5! a o I I I 4 In ventors I Ra bed: 11 S andber I Lawrencezi' .S'teimen By th ezr lttorney R. N. SANDBERG ET'AL PRACTICE AMMUNITION ROUNDS Marci: 11, 1958 s Sheet's-Sheed' 2 Filed Nov. 26, 1954 Inventors Robert MSandberg Lawrence ESteime/z 55y thelrAttor/zqy United States Patent PRACTICE AMMUNITION ROUNDS Robert N. Sandberg, Beverly, and Lawrence E. Steimen, Topsfield, Mass., assignors to United Shoe Machinery gorporatiomflemington, N. 1., a corporation of New ersey Application November 26, 1954, Serial No. 471,164 4 Claims. (Cl. 10241) The present invention relates to ammunition and more particularly to an improved practice ammunition round for large bore rifles which is adapted to fire small caliber rounds in training military personnel.

Training military personnel in the use of relatively large rifles presents many problems. Included in these problems is the high cost of ammunition, most especially when one considers the number of rounds which must be fired in order for any one person or team to become proficient in the use of a weapon. A further problem,- particularly. with respect to recoilless weapons, is the considerable physical risk involved, especially during the initial portion of the training period. The recoilless weapons have the additional hazard of the flaming gases which are fired from the rear of the gun the lethal range of which extends rearwardly of the gun in the order of 150 feet.

Primarily for the reasons stated above, socalled drill rounds or practice rounds have been devised which provide means for firing a small caliber round from within an empty shell casing of the larger round. In order to train military personnel with the greatest proficiency it is necessary that the drill round meet several requirements. The drill round should be of the same size and weight as the real round which it simulates. It is further desirable, where the drill round simulates a round of ammunition for a recoilless rifle, that means be provided for creating a flame extending rearwardly of the weapon, which is less hazardous but which is sufficient to teach respect for the dangers of this type of gun. It is of great importance also that the mounting means for the small caliber round be readily adjustable so that the accuracy of the small round will give a true indication of where a real round would have hit. Furthermore, it is of great importance that the spent small caliber casing be easily and readily removable from the drill round and that it be possible to insert a new small caliber round in a rapid and eificient manner, as it is often necessary to conduct such activities under stress and/ or in the nighttime.

It is an object of the present invention to provide a drill or practice round of ammunition wherein improved means are provided for mounting a small caliber barrel within the hollow shell of the practice round.

It is a further object of the present invention to provide a drill or practice round of ammunition wherein improved means are provided for inserting a small caliber round therein and for removing the casing of the small round after it has been fired.

In accordance with the various features of the present invention a fixed member is secured at the base of and within a hollow casing of a relatively large bore ammunition round. A short barrel having an integral firing chamber is'mounted concentrically of the casing with its firing chamber end threaded into the fixed member. A rotatable member is mounted in the base portion of the fixed member and carries a cap which acts as a breechblock for closing the base end of the drill round. I

2,26,145 Patented Mar. 11, 1958 The cap may be slid tranversely of the member.

spent casing of small caliber ammunition. An extractor pin is provided which, by reason of camming surfaces formed on the rotatable member, will positively eject a spent casing and also be positively brought into register with a newly introduced round.

The above and other features of the invention, includ-' ing various novel details of construction and combina-' tion of parts, will now be more particularly described by reference to the accompanying drawings and pointed;

A and on an enlarged scale with certain portions of the casing being broken away;

Fig. 3 is a section taken on the line IIIIIl in Fig. 2;-

Fig. 4 is a section taken on the line IVIY in Fig. 1;

Fig. 5 is a section taken along the line V--V in Fig. 3 with the end cap being shown in a displaced position;

Fig. 6 is a partial section taken on the line VI--VI in Fig. 5;

Fig. 7 is a view similar to Fig. 5 with the end cap having been rotated to remove a spent casing;

Fig. 8 is a section taken on the line VIII--VIII in Fig. 5 and on a further enlarged scale;

Fig. 9 is a section taken on the line IXIX in Fig. 7;

Fig. 10 is a section taken on the line XX in Fig. 5 showing the extractor in detail;

Fig. 11 is a view similar to Fig. 10 showing the extractor in intermediate operating position;

Fig. 12 is a view similar to Fig. 10 showing the ex tractor in a further operating position; and

Fig. 13 is an exploded view of the various elements comprising the end cap and extractor operating means.

Referring to Fig. l, the outline of a typical recoilless weapon round or projectile 20 may be seen. It is composed of a perforated powder casing 22 and a modified head 24. A short barrel 26 is mounted concentrically of the round 20 and has a firing chamber 28 into which small caliber cartridges B are inserted as in Fig. 3. The forward end of the barrel 26 is carried in a collar 30 which is adjustably mounted with respect to the head 24 by four screws 32 (Fig. 4). By proper adjustment of the screws 32 it is possible to adjust the forward end; of the barrel so that the small caliber cartridge will fire with the same accuracy as a larger round would.

The rear end of the barrel 26, that is, the firing cham er 28, is threaded into a member 38 which is fixed with respect to the casing 22 by a plurality of screws 40 the heads of which are flush with the outer diameter of said casing. A rotatable member 42 is mounted on the rear end of the fixed member 38 by three pins 44 which are:

carried by the fixed member 38 and extend into an annular groove 45 formed on the member 42 (Figs. 3 and 5). An end cap 46 which acts as a breechblock to close the end of the firing chamber is slidably mounted on the rotatable member 42 by an integral slide 48 which rides. in an undercut groove 50 formed in said rotatable mom ber. The slide 48 has an extension 52 which is received by a corresponding slot formed in the casing 22 and in. the fixed member 33 to assure proper alinement between said fixed member and the rotatable member 42.

Normally the cap 46 is maintained in the position shoving drill round. to bring a hole into alinement with the bore of the short: barrel and also to provide means for rotating the rotatable:

The hole in the cap provides access to theshort barrel for inserting a new round or extracting ain Fig. 3 by a headed pin 54 which is journaled in the rotatable member 42 and extends into an arcuate slot 56 formed in the member 38- (Figs. 3 and The head ofthe pin 54 enters a hole 62 formed in the cap 46.- The pin 54 is maintained in this normal position by a corn pression spring 58 acting between the-head of the pin and the member 42. A ridge 60 formed'on the head of the pin 54 prevents it from passingcompletely through the hole 62.

The firing pin mechanism normally employed in recoilless weapons of the type for which this drill round is intended, is indicated at P with a firing pin p mounted concentrically with respect to the round of ammunition. The diameter of the firing pin p is substantially greater than the diameter of the firing cap of the cartridge B. Therefore. it is not possible to fire the cartridge B by strikingit directly with pin p unless the gun itself were modified by changing the firing pin mechanism. For that reason an intermediary firing pin 64 is mounted in a plug 66 in the cap 46. It will be noted that the outer diameter of the pin 64 is substantially the same as that of the pin p, while the inner diameter of the pin 64 is much less and approximates the diameter of the firing pin normally used for the smaller caliber cartridge B. A hole 68 is provided in the firing pin 64 to receive the lower end of a centering spring member 70 the upper end of which is threaded into the cap 46. Likewise a hole 72 has been formed inthe plug 66 to permit passage of the spring 70. It will be noted that the outer portions of the hole 68 are beveled to permit axial movement of the firingpin 64.

In firing the cartridge B it is necessary that the rear end of the cartridge be in intimate contact with the inner face of the plug 66 and yet it is also important that there be no interference between the plug 66 and the end of the cartridge B. This means that the rear end of the firing chamber 28 must be adjusted with great accuracy with respect to the plug 66. To facilitate this adjustment, grooves 74 are cut into the firing chamber 28, as best seen in Fig. 3. When the barrel 26 is properly adjusted a pin 76, slidably mounted on the member 38, seats in the appropriate groove 74. When it is desired to adjust the barrel 26, normally done only when the drill round is first assembled, the fixed member 38, as well as the other members secured thereto, are removed from the casing 22 by removal of the screws 40. The grooves 74 have sloping surfaces so that the barrel 26 may be rotated inwardly or outwardly with respect to the member 38 against the yielding action of a spring 78 acting on, the pin 76. A screw 80 riding in a slot 82 formed in the pin 76 maintains the pin in proper axial alinement with the grooves 74. It will be noted that when the fixed member 38.is assembled in the casing 22 there can be no rotation of the barrel 26 since the end of the pin 76 abuts the. inner Wall of the casing 22.

An extractor 84 is provided for insuring the positive ejection of a spent casing from the firing chamber 28. The extractor 84 is formed integrally with a pin 86 which is slideably and rotatably mounted in the fixed member 38. A spring 88 normally urges the pin 86 and the extractor 84 rearwardly toward the base portion of the drill round. Adjacent the pin 86 is a fixed pin 90 secured to the fixed member 38. A torsion spring-92 acting between the pin 90 and the extractor 84 normally tends to rotate the extractor 84 in a clockwise direction (as seen in Fig. 5).

It will be noted that the outer extreme end 94 of the extractor 84 is formed with a. circular profile and has a wedge shape which is specifically adapted to fit under the flange which is conventionally formed at the base of small caliber ammunition.

There are three camming surfaces which control the movements. of the extractor 84. A cam surface 96 formed on. the rotatable member 42 cooperates with the upper end of the extractor pin 86 to insure positive seatingof the extractor pin. A cam. surface 98 formed adjacent the outer end 94 of the extractor 84 cooperates with a projection 180 formed on the rotatable member 42 to insure positive extraction of a spent casing. The fixed pin is formed with a conical portion 102 which cooperates With an edge 104 of the extractor 84 and the spring 92 to control rotational-motion of the extractor 84. A more detailed description of the function of these various camming surfaces will be given in the description-of the operation of the present device below.

After the cartridge B (see in Fig. 3) has been fired, its casing must be extracted from the dummy round or, in case the cartridge B fails to fire, then the entire cartridge must be extracted. In order to accomplish this the pin 54 is manually depressed to permit the end cap 46 to be slid upwardly to bring the opening 62 into alinement with the barrel 26, as is seen in Figs. 5 and 6. In order to remove the casing of the cartridge B the rotatable member 42 is rotated by using the end cap 46'as a handle. Theend cap and rotatable member 42 are thus brought into a position relative to the fixed member 38 as shown in Fig. 7. The amount of rotational movement which may be imparted to the member 42 is limited by the arcuate: slot 56 formed in the fixed member 38 into which the pin 54 extends. During the initial rotational movernent of the member 42 the. head of the extractor pin 86 first moves away from or along the camming surface 96 allowing the extractor to be urged rearwardly by the spring 88. This condition is indicated in Fig. 11 where the head of the pin 86 is seen moving rearwardly along the surface 96 thereby extracting the casing. However, in many instances the casing has been expanded when the cartridge B has been fired so thatit will not be extracted under the light force which is provided by the spring 88. In such instances as rotational movement is imparted to the rotating member 42 the extractor remains in its depressed position through a substantial portion of the rotational movement of the member 42, until the cam surface 98 engages the projection 100 thereby positively camming the extractor 84 outwardly and carrying the casing with it. It is only necessary to break the initial hold of the casing since it has a very slight taper; thus, once this hold is broken the casing will fall freely from the firing chamber and through the opening 62. As the extractor 84 moves rearwardly under the action of the spring 88 its edge 104 engages the conical section 102 of the pin 90 thereby rotating the extractor to the position shown in Fig. 7 so that free access is provided for. inserting a new round B.

With the parts of the drill round in the position shown in Fig. 7 a new cartridge B may be inserted. The new cartridge is injected into the firing chamber 28 as far as possible. The rotating member 42 is then rotated from the position shown in Fig. 7 to the position shown in Fig. 5 by manual manipulation of the end cap 46. As this last-mentioned rotational movement is imparted to the member 42 the camming surface 98 passes above the projection 100 and then during the final portion of the rotational. movement the head of the extractor pin 86 engages the cam surface 96 thereby depressing the extractor 84. The surface 104' of the extractor 84 moves away from the conical section 102 of the pin 90 allowing the extractor 84 torotate in a clockwise direction under the influence of the spring 92. Continued rotational movement of the member 42, causes continued depression of the extractor 84 "so that when the parts assume the position shown in Fig. 5" the outer end 94 of the extractor 84 is correctly positioned beneath the flange of the cartridge B. At the same time the slide extension 52 is in alinement with the corresponding groove formed inthe casing 22 and the fixed member 38. The end cap 46. is then displaced from the position shown in. Fig. 6 to the position shown in Fig. 3. During this movement of the end cap a bevel formed on the plug 66 rams the cartridge B- completely into the firing chamher 28. The end cap is locked in a firing or operative position as the pin 54 enters the hole 62.

When it is desired to insert a cartridge B into the firing chamber 28, where a spent casing has not been removed immediately beforehand, it is not necessary to rotate the member 42 to the position shown in Fig. 7 in order to insert a new round. It is only necessary to slide the end cap 46 to the position shown in Figs. 5 and 6.

The extractor 84 is correctly positioned with respect to the desired location of the flange of a cartridge by the cam surface 96. Thus a new cartridge may be inserted through the hole 62 and into the firing chamber 28 as the extractor 84 will be displaced in a counterclockwise direction against the yieldable action of the spring 92. The end cap then may be returned to the position shown in Fig. 3 and will be ready for firing.

In use the drill round 20 is inserted into a recoilless rifle (not shown) in the same manner as conventional ammunition. The firing pin mechanism P will be disposed relative to the round as is shown in Fig. 3. When the rifle is fired the firing pin 1 will strike the intermediate firing pin 64, causing the smaller diameter of the pin 64 to strike the percussion cap of the cartridge B. As the cartridge B is fired through the barrel 26 the gases of combustion will escape through holes 106 (Fig. 4) and then through the perforated casing 22 toward the rear of the gun in the same manner as the larger volume of gases from the larger round would be discharged. Thus a flame is provided from the rear of the rifle which is less dangerous than that from a larger round but which is sufficient to teach respect for the inherent dangers of recoilless weapons.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

l. A practice round of ammunition comprising an outer shell which simulates a round of ammunition for large bore rifles, a barrel from which a small caliber cartridge may be fired, said barrel being mounted concentrically of said shell, a member fixed to the base of said shell and carrying the firing chamber end of said barrel, a rotatable member mounted on said fixed member, an end cap which acts as a breechblock and which is laterally slidable on said rotatable member for opening and closing the firing chamber end of said barrel, an extractor for removing the casing of a spent cartridge fired from said barrel, said extractor being slidably and rotatably mounted in said fixed member, spring means for urging said extractor rearwardly of said shell, further spring means for rotating said extractor toward said barrel, and cam means on said rotatable member which are efiective upon rotation of said rotatable member to enact with a surface on said extractor for positively displacing the extractor rearwardly to remove the casing of a spent cartridge fired from said barrel.

2. A practice round of ammunition comprising an outer shell which simulates a round of ammunition for large bore rifles, a barrel from which a small caliber cartridge may be fired, said barrel being mounted concentrically of said shell, a member fixed to the base of said 6 shell and carrying the firing chamber end of said barrel, a rotatable member mounted on said fixed member, an end cap which acts as a breechblock and which is laterally slidable on said rotatable member for opening and iclosing the firing chamber end of said barrel, an extractor for removing the casing of a spent cartridge fired from said barrel, said extractor being slidably and rotatably mounted in said fixed member, spring means for urging said extractor rearwardly of said shell, further spring means for rotating said extractor toward said barrel, cam means on said rotatable member which are effective upon rotation of said rotatable member to coact with a surface on said extractor for positively displacing the extractor rearwardly to remove the casing of a spent cartridge fired from said barrel, and cam means on said fixed member which are effective upon rearward displacement of said extractor to rotate said extractor away from said barrel.

3. A practice round of ammunition comprising an outer shell which simulates a round of ammunition for large bore rifles, a barrel from which a small caliber cartridge may be fired, said barrel being mounted concentrically of said shell, a member fixed to the base of said shell and carrying the firing chamber end of said barrel, a rotatable member mounted on said fixed member, an end cap which acts as a breechblock and which is laterally slidable on said rotatable member for opening and closing the firing chamber end of said barrel, an extractor for removing the casing of a spent cartridge fired from said barrel, said extractor being slidably and rotatably mounted in said fixed member, spring means for urging said extractor rearwardly of said shell, and cam means on said rotatable member which are elfective in one position of said rotatable member to positively locate said extractor with respect to said barrel so that the extractor will underlie the end flange of the cartridge in said barrel.

4. A practice round of ammunition comprising an outer shell which simulates a round of ammunition for large bore rifles, a barrel from which a small caliber cartridge may be fired, said barrel being mounted concentrically of said shell, a member fixed to the base of said shell and carrying the firing chamber end of said barrel, a rotatable member mounted on said fixed member, an end cap which acts as a breechblock and which is laterally slidable on said rotatable member for opening and closing the firing chamber end of said barrel, said end cap having a hole formed therein, and a pin which yieldably enters said hole normally to prevent lateral displacement of said cap, said cap being mounted with respect to said rotatable member so that upon displacement of said pin said hole may be brought into alinement with said barrel as lateral movement is imparted to said cap.

References Cited in the file of this patent UNITED STATES PATENTS 2,541,025 Bluford et al Feb. 13, 1951 FOREIGN PATENTS 707,367 Great Britain Apr. 14, 1954 

